Power-operated universal chuck



May 20, 1952 T. w. BARNES POWER-OPERATED UNIVERSAL CX- IUCK 4Sheets-Sheet 1 Filed Aug. 26, 1949 T. W. BARNES May 20, 1952POWER-OPERATEF UNIVERS AL CHUCK 4 Sheets-Sheet 2 Filed Aug. 26, 1949 y0, 1952 T. w. BARNES 2,597,280

POWER-OPERATED UNIVERSAL CHUCK Filed Aug. 26, 1949 4 Sheets-Sheet 3 T.W. BARNES POWER-OPERATED UNIVERSAL CHUCK May 20, 1952 4 Sheets-Sheet 4Filed Aug. 26, 1949 Patented May 20, 1952 Tracy W. Barnes, WebsterGroves, Mo., assignor to John Ramming Machine Company, St. Louis, Mo., acorporation of Missouri Application August 26, 19 49, Serial N 0.112,600

This invention relates to universal chucks, and more particularly topower-operated chucks of this class.

The object. of the invention is to provide in a chuck, particularly ofthe power-operated type, a compact, reliable and safe constructionhaving jaws which are simultaneously (universally) operated both formanual diametral adjustment and for power-gripping operation at anygiven adjustment; the provision of a chuck of this class having nounsafe external protrusions, and wherein no central draw mechanism isemployed, thus providing for a large unobstructed central opening whichwill accommodate a large range of sizes of objects to be gripped, suchas, for example, a large range of sizes of pipe to be threaded orotherwise machined; and the provision of a chuck of the class describedwhich may be power-operated to grip and release while rotating. Otherobjects will be in part apparent and in part pointed out hereinafter.

Briefly, the invention consists in an annular chuck housing having anenclosing annular rotary scroll ring. Within the chuck housing is aspider which carries a plurality (preferably three) jaw carriers whichare simultaneously radially controlled by the scroll ring. Thesecarriers support jaws which are radially adjustable with respect to thecarriers, and which simultaneously may be given spring-returned radialmovements with respect thereto, to provide a gripping action at anygiven adjustment of the carriers by the scroll ring. The gripping actionis provided for by a plurality of wedges which are axially movable inany radial position which they are permitted to assume as the carriersare moved. The wedges have radial sliding connections with an axiallymovable piston so that they may be driven to wedging and unwedgingpositions in any radially adjusted positions of the assemblies of jawcarriers and jaws. The piston is also spring-returnable to releaseposition. Fluid (preferably air) for operating the piston is introducedand exhausted through a stationary distributor ring associated with thechuck housing, the latter interiorly constituting the cylinder for thepiston, and by this means chucking operations may be carried out whilethe chuck is rotating.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which willbe exemplified in the structures hereinafter describedlland the scope ofthe application of which will-be indicated in the following claims.

3 Claims. (Cl; 279-121) In the accompanying drawings, in which one ofvarious possible embodiments of the invention is illustrated,

Fig. 1 is a side elevation on a reduced scale of a chuck embodying theinvention;

Fig. 2 is an end elevation, viewed from the right of Fig. l; H

Fig. 3 is a median section on a larger scale, taken on line 33 of Fig.2;

Fig. 4 is a sectional view, the upper half of which is taken in theplane AA of Fig. 3, the

A lower right-hand quadrant of which is taken in p the plane B-B of Fig.3, and the lower left quadrant of which is taken in the plane 0-0 ofFig. 3; Fig. 5 is a horizontal section taken on line 5-5 of Fig. 4,being enlarged;

Fig. 6 is a cross section taken on line 66 of Fig. 3;

Fig. 7 is a cross section taken on line 1-1 of Fig. 5;

Fig. 8 is an end view of an operating piston per se as viewed from theright of Fig. 3; and

Figs. 9, wand 11 are views similar to certain upper wedging parts ofFig. 3 illustrating various applied, which includes a rotary member 3.At 5 is shown an adaptor plate by means of which the chuck of thepresent invention is mounted (see fasteners l in Fig. 3).

At numeral 9 is shown a cup-shaped chuck housing having a hub II. A

. central spider I3 is attached to the interior of the hub I l byfasteners l5 (Fig. 3). A part of this spider is constituted by an innersleeve 2 ing within the hub H.

which inwardly defines an extension of the open- The end of this sleeve2 carries lugs 3'! defining radial guide passages 39 which will bedescribed below.

Covering the front of the housing 9 (except at the central portion) is arotary annular scroll,

. cam ring or plate I! (Figs. 3, 4 and 6). This plate space for thereception of large workpieces. ztary attachment to housing 9 of scrollI1 is achas a hole through it coaxial with the hole within hub H andsleeve 2. The result is a continuous hollow' central cylinder 6 ofgenerous diameter, providing a large amount of unobstructed centralcomplished by keys H! which are fastened at inerva-ls to the front endof the housing 9 by screws l. the keys engaging in a groove 23 cut intothe ring N (Fig. 3). Openings 25 in the ring provide access to thescrews (Fig. 4). The periphery of the ring I! is also provided withholes 21 for the reception of a suitable lever bar for turning the ringinto any desired angular position on the housing 9. The inside face ofthe ring I1 is provided with a spiral or scroll thread or cam 29 (Fig.6). I

Behind the scroll ring H are three jaw carriers 3| (for a detail seeFig. '7) which have segmental threads 33 engaging the scroll thread 29.These carriers 3| are radially slidable in slots 39 of the lugs 31 inthe spider l3. Each carrier is channelshaped (Fig. and includes attachedlateral keys 35 which slide in sidewise radial grooves in the slots 39.The channel 4| of each carrier 3| is blocked off at the top by means ofan inserted thrust block 43. The thrust block 43 is preferably achangeable insert in the jaw carrier 3|, instead of integral as it mightbe, for convenience in providing a special (and renewable) hard surfaceat the point of thrust.

On the top of each block is a spring socket 45 for a compression spring41 which reacts from the socket against the head 49 of a bolt 5|. Eachbolt slides through a hole 8 in the bottom of the socket 45 and isthreaded into a gripper jaw 53. Each jaw 53 slides in the respectivechannel 4| of its carrier 3|. The bottom of each thrust block 43 and thetop of each jaw 53 are relatively angled for the reception of a forkedwedge 55. The fork shape of the wedge is to accommodate motion relativethe bolt 5|. Each bolt 5| is accessible for adjusting its spring 41through a threaded access plug 51.

The rear end of each fork 55 is provided with grooves 59 for slidingengagement within pairs of parallel dovetail bars 6| (Figs. 3 and 5)held in spaced radial positions on the front of a piston 63 (see alsoFig. 8). The bars 6| are held in place by screws 65.

The form of the piston 63 is best shown in Fig. 8. It is cup-shaped,having a rim 61 and a bottom 69 wherein is an opening 1|, the latter forsurrounding the central cylindric portion 2 of the spider |3. In the rim61 are castellations '13, for clearing the jaw carriers when thelatterare in their outermost positions. On the face of the piston is carried apacking ring 15, which has peripheral sealing lips with the insidecylindric surface of the housing 9 and the outside cylindric surface of2. The packing ring 15 is held in position by a plate 11, held down byscrews 19. The packing includes openings 8| for permitting the face ofthe piston 63 to contact stops 83 threaded into the hub H, which limitsretractive movement of the piston 63. Retractivespring-return isprovided by springs 85, reacting from spring seats 81 in the spider l3(Fig. 3).

In order to bring operating fluid (in the present case air) to thepiston 63, the hub H is ported as shown at 89 (Fig. 3). Around the hubis car.- ried a distributor ring 9| which is centrally grooved as shownat 93. On each side of the groove 93 are packing rings 95. The groove 93is provided with an inlet tap 91 for accepting an air pipe H) (see Fig.l) in which are suitable control auxiliaries such as a three-way inletand exhaust valve, filter, pressure regulator and lubricator (notshown). Since air and fluid line auxiliaries of this type arewell-known, no further description or showingis needed for those skilledin the art. The purpose of the distributorring 9| is to allow forintroduction and release, of air to and from the spacebehindthe pistonmany angular position of the chuck, although the distributor ring isstationary. At numeral 99 is shown an extension on the ring forcooperation with a holding dog |0| fastened to the bed of the machinewhich carries the chuck. This holds the ring stationary while the hub Irevolves in it.

Operation is as follows:

The chuck is mounted on the rotary member 3 by means of the adaptor 5,the distributor ring 9| being held against rotation by the dog It) andthe remaining parts of the chuck being rotary as a unit. The member tobe chucked, which may be of considerable size because of the largecentral opening provided at 6, is introduced into or through saidopening. This is done after the scroll ring I! has been adjusted by useof a bar in one of the openings 21, so that the jaw carriers 3| andattached jaws 53 are clear. In practice, suitable index characters I01are placed on an outer periphery of the ring I! with a pointer indexmark I05 on the outside of the chuck housing 9, to indicate the maximumdiameter of work that will be accepted at a given adjustment (Fi 1).

Next the air may be turned on, which admits pressure behind the piston63, forcing it forward. This drives the wedges 55 forward (to the right)between the thrust block 43 and the upper outer ends of the jaws. Thiswedges the jaws inward to grip the work. After the desired rotaryoperation has been performed on the work, the air is released, whereuponthe springs return the piston 63 to withdraw the wedges 55. The springs.41 then retract the jaws outward to release the work. Thepower-gripping and releasing operations may be performed either whilethe chuck is stationary or rotating.

Figs. 3, 10, 9 and 11 illustrate certain advantages of the invention. Bycomparing Figs. 3 and 9, it will be seen how, when the air is turned off(piston 63 retracted), the scroll ring may be rotated so that eachentire assembly of jaw carrier 3|, jaw 53 and wedge 55 is carried in orout, the sliding dovetail connection between each jaw assembly and thepiston maintaining the driving connection with the piston under anyradially adjusted condition. In Fig. 3 is shown a maximum outwardadjustment for large work L, and in Fig. 9 a maximum inward one forsmall work S. This adjustment must be made while the chuck housing 9 isstationary or nearly so.

Figs. 3, 9, 10 and 11 demonstrate how with respect to any size ofworkpiece the jaws are moved from a non-clamping or radially retractedposition (such as shown in Figs. 3 and 9) to the clamping position shownin said Figs. 10 and 11, respectively. This involves turning on the airto push the piston forward. The range of work accommodated is clear fromthese figures. It will be understood that in the case where theseworkpieces are long, the rotary parts in the headstock l which supportthe chuck are hollow, so that they may, as usual, be fed through theheadstock from the rear into the chuck.

It will be observed that the cooperation between the threads 29 of thescroll ring and the segmental threads 33 on the jaw carriers 3| are ineffect camming means between these pieces and it will be understood thatother simultaneously operating cam means may be used between a membersuch as I! and the jaw carrier within. the scope of the invention.andthe term scroll comprehends these. 3 A feature of the invention.which is clear-from Fig. 1 is the absence from the outside of thehousing 9 or scroll ring it of any protruding adjusting elements. Thiscontributes substantially to the safety of operation of the device.

By having the piston 69 spring-retractible and an axially interlockedconnection between it and the wedges 55, the jaw-retracting springs 41are not required to return the piston by reaction through the wedges.These springs a? thus perform jaw-retracting functions, while thesprings 85 produce piston-retractive functions. This separation of theretractive functions of the two sets of springs ensures a reliableretractive operation on all parts. Contributing to this feature is thefact that the wedges 55 have the axially interlocked, radially slidabledovetail connection with the piston which has the additional function ofallowing the piston to withdraw the wedges upon retraction and allowingthe wedges to move with the jaw and jaw carrier assemblies upon rotatingthe scroll ring without binding at sliding connections between thewedges and the piston.

It will be observed in connection with Figs. 3, and 9-11, that thefollowing auxiliary devices on the periphery of the chuck shown on Fig.3 have not been repeated in the rim section of Figs. 9-11, inasmuch asthe latter are designed primarily to show alternate positions of theprimary elements of the chuck, i. e., a threaded as illustrative and notin a limiting sense.

I claim: 1. A chuck comprising a support, jaw carriers carried by andguided for radial movement rela- 6 tive to the support, jaws carried byand guided for radial movement relative to the jaw carriers, wedgescarried by and guided for axial movement relative to the jaw carriers,and a wedge driving member carried by and guided for axial movementrelative to the support, axial movement of the wedge driving membercausing simultaneous axial movement of all wedges, said wedges havingradial sliding connections with the wedge driving member and beingmovable between the jaw carriers and jaws to cause inward radialmovements of the jaws.

2. A chuck as set forth in claim 1, wherein the radial slidingconnections between the wedges and the wedge driving member are adaptedboth to advance and retract the wedges upon axial movement in oppositedirections of the wedge driving member, and spring means between the jawcarriers and the jaws adapted to bias the jaws outward relative to thecarriers.

3. A chuck set forth in claim 1, wherein the radial sliding connectionsbetween the wedges and the wedge driving member are adapted both toadvance and retract the wedges upon axial movement in oppositedirections of the wedge driving member, wherein spring means areemployed between the jaw carriers and the jaws adapted to bias the jawsoutward relative to the carriers, and wherein the wedge driving memberis power driven in a direction to force the wedges between the jawcarriers and jaws but springreturned to retract said wedges.

. TRACY W. BARNES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,364,783 Morgan Jan. 4, 19211,469,360 Cullen Oct. 2, 1923 1,608,462 Cutler Nov. 23, 1926 2,191,371Church Feb. 20, 1940 2,474,771 Amstutz et al June 28, 1949

